Application of fault tree analysis to longitudinal control in automated highway systems

Intelligent Transportation Systems (ITS) is a group of technologies that pr ovide the tools to help address many of the current surface transportation problems. ITS applies technologies in such fields as electronics, communica tions, control and information processing to surface transportation needs. Automated Highway Systems (AHS) is one of the most important components of ITS which embodies the full development of automatic vehicle control to ach ieve the highest levels of efficiency and safety on the highway. The reliab ility and availability of the AHS using a fault tree and a mathematical mod el of its failure is presented in this paper. The proper functioning of the system is dependent on many components including the communication system between successive vehicles, data acquisition system, transmitter and other software and hardware. Failure on the part of these elements affects the r eliability of the whole system. This study presents the application of faul t tree analysis to model failure mechanisms of AHS. Qualitative and quantit ative analysis are performed on the fault tree. The analysis includes the d etermination of system reliability, system unavailability, and importance o f subsystem components. Graphs are presented for illustrating the availabil ity and reliability of the subsystems of AHS. The reliability and availabil ity of AHS for conducting safety analysis, risk analysis and cost-benefit a nalysis can be determined from these graphs. Successful implementation of I TS technologies, to a large extent, win depend on the outcome of the aforem entioned analyses.